Cumulative Frequency Flashcards
How do you make a cumulative frequency column?
Add the frequencies together as you move down the frequency table
How do you plot a Cumulative Frequency Graph?
Plot the upper class limit against the cumulative frequency
Join the points with a straight line.
How do you find the Median from a c.f. graph?
Find the total frequency.
Divide by two.
Draw a line across at this point.
Read the value on the x-axis.
How do you find the IQR from a cumulative frequency graph?
Read the c.f. graph at the Upper quartile and the Lower quartile (of the total frequencies).
IQR = UQ - LQ
How do you find how many people were higher than a given amount?
Find the given amount on the x-axis.
Draw a line up at this point.
Read the cumulative frequency.
Subtract this amount off the total frequency.
